Sebum is a natural product from the sebaceous gland which, together with sweat produced by the eccrine or aprocrine glands, constitutes a natural moisturizer for the epidermis of the skin. It is reported that the sebaceous gland produces squalene, triglycerides, aliphatic waxes, cholesterol waxes and possibly free cholesterol (Stewart, M. E., Semin. Dermatol. 11, 100-105 (1992)). The action of bacterial lipases on the skin converts a variable portion of the triglycerides into free fatty acids. It is believed that the short color lasting or poor color staying may be attributed to fatty acids.
Thus, it would be advantageous to remove fatty acids from the surface of the skin because this removal would reduce the unfavorable effects by sebum such as short lasting and poor staying power of make-up on that surface.
There are some known substances which can absorb oily ingredients such as fatty acids. For example, JP-A-H09-227792 cites zinc oxide particles as a sebum absorber. However, zinc oxide particles, in particular zinc oxide nano-particles are suspected to have environmental toxicity.